The present invention relates to a nut of a planetary roller screw drive. In such planetary roller screw drives, a spindle nut is typically arranged on a threaded spindle, wherein planets that are arranged distributed around the periphery in an annular gap bounded by the spindle nut and the threaded spindle are in rolling engagement, on one side, with the threaded spindle and are in rolling engagement, on the other side, with the spindle nut. When the spindle nut and the threaded spindle are rotated relative to each other, this relative rotation is converted into an axial relative displacement between the threaded spindle and the spindle nut. In the axial directions, a positive-fit connection is established in planetary roller screw drives due to the rolling engagement of the planets. Without relative rotations between the spindle nut and the threaded spindle, no axial relative displacement is produced.
From DE 10 2008 008013 B3, for example, a planetary roller screw drive has become known with a nut that is provided on the inner periphery on each of its two axial ends with a groove profile, wherein planets on its two ends are also provided with groove profiles and wherein these planets engage with their groove profiles in the groove profiles of the nut.
The one groove profile formed on the nut for the one end of the planets and the other groove profile for the other end of the planets are formed on a common part of the nut and are thus arranged at a fixed distance relative to each other. This distance is tailored perfectly to the planets, so that the planets engage perfectly with their groove profiles provided on the ends in the groove profiles provided on the ends of the nut. The axial distance of the two groove profiles provided on the nut is fixed in such a nut; that is, it is not designed for a change in position of the two groove profiles relative to each other to be possible.
The groove profile in these known planetary roller screw drives or those according to the invention can consist of a plurality of grooves that are arranged one behind the other in the axial direction and have a closed annular shape on the peripheral side—as in the case of the publication noted above—and are arranged parallel to each other, wherein these grooves can lie in a plane that is arranged perpendicular to the axis of the planets and the axis of the nut. Two grooves that are arranged adjacent to each other can be bounded by a common groove connecting piece. In the rolling engagement of the planets with the nut, the groove connecting pieces of the planets engage in the grooves of the nut and the groove connecting pieces of the nut engage in the grooves of the planets. In other words: the groove profiles of the planets and of the nut engage in each other.
Between the two groove profiles of the nut there is an open space in which the planets engage with a radially enlarged middle section without contact to the nut. Such grooves can be produced, for example, in a metal-cutting process. Thus it is possible to produce both the groove profiles on the end and also the open space with a boring tool. However, such metal-cutting processing is complicated.